I had my computer completely unplugged for a few weeks and then I just tried to boot it today but I got a cmos checksum error...so I replaced the cmos battery. This didn't work! I still get this error AND I have no keyboard. So when I try to press F1 as I am told I get nothing. It appears that both the keyboard and mouse don't work because the lights on the keyboard don't light up and my optical mouse doesn't light up either (and of course they are plugged in). Does anyone know what could be going on here?? Thanks so much, Evan.

Battery installed upside down?

Make sure the + is in the correct position . http://www.mycableshop.com/techarticles/CMOSBattery.htm http://www.pcmech.com/show/motherboards/80/ ===================================== Press F1 to continue message . Press F1 to continue, DEL to enter setup" it's likely that your CMOS is corrupt. When you see that message, go into CMOS (press DEL) and then hit F10 to save and exit and unless your battery is weak, you should not see that again. You don't have to change anything - go into it and save and exit. That's all there is to it. More here . Prompt to press F1/F2 each time computer boots: http://www.computerhope.com/issues/ch000301.htm http://support.microsoft.com/?kbid=263318

Make sure the KB is plugged into the correct connnection. Go into cmos and if you have the option to 'reset configuration data' enable that.

http://www.computerhope.com/issues/ch000237.htm Issue: CMOS checksum error. Cause: This issue can be caused by any of the following: 1. Incorrectly configured CMOS settings 2. Disconnecting power from computer without shutting down computer Solution: Incorrect configured CMOS settings Attempt to reboot the computer. If error still occurs after rebooting the computer enter CMOS setup and check all values. If you have cleared and or flashed the BIOS ensure that the time and date are set correctly then save changes and reboot. If you have a Phoenix BIOS and have an option for 'Reset Configuration Data', set this value to 'Yes' and save and exit the CMOS. Disconnecting power from computer without shutting down computer If disconnecting the power from the computer while still operational this could cause the CMOS to become corrupt. Ensure that the computer is ready to be shut off before turning off the computer. If you have a laptop computer ensure that the battery is charged before disconnecting the power connection. Additional information about CMOS and how to get into it: http://www.computerhope.com/help/cmos.htm

Hi Evan and all, Are you SURE the keyboard and mouse are not plugged into the WRONG ports? Even though PS/2 mouse and keyboard ports are PHYSICALLY identical (another STUPID decision by IBM), they are NOT interchangeable (wired differently internally). Swap the mouse and keyboard connections, and let us know what happens. HTH Pistol Pete

Apologies to DAVEINCAPS! Once I re-read this page, I realized that I must have scrolled right past your response, DAVEINCAPS; I think you hit the nail right on the head, so your next beer is on me. Just tell the barmaid to put it on my tab. Don't worry, she knows me; sometimes, I think they ALL know me ;-) Pete